1. Field of the Invention
The present invention relates generally to a method and apparatus for preventing illegal reuse of Digital Right Management (DRM) content in a portable terminal, and more particularly to a method and apparatus for preventing illegal reuse of DRM content by using information on a Right Object (RO) file indicating a right to use the DRM content.
2. Description of the Related Art
Recently, the prolific advancement in electrical and electronics industries has spawned the development of various digital technologies. As a result, DRM is being widely used. The DRM is a technique for preventing illegal copying of digital content in order to secure right and interest of a digital content provider and for collectively supporting accounting, distribution and management in the use of the digital content.
According to the DRM, the use of specific DRM content is permitted only in devices for which a right to use the DRM content has been attained. Since the DRM content is composed of an encoded content file and an RO file having a key capable of decoding the encoded content file, the content cannot be used in the device if RO cannot be properly obtained.
In addition, users frequently replace their portable terminals. To cope with this trend, a technique is provided in which DRM content used in an old portable terminal can also be used in a new portable terminal. For example, referring to FIG. 1, a user of specific content 150 through a terminal-A 100, changes his or her portable phone to a terminal-B 120. In this case, an RO for the specific content 150 stored in the terminal-A 100 is backed up (step 110), restored in terminal-B 102 (step 130) and is then subject to a user authentication process (step 132). Accordingly, the specific content 150 can be used in terminal-B 102. When terminal-A 100 backs up the RO, an RO backup file is created in terminal-A 100, and the RO is deleted. The RO backup file may be stored in another terminal or be moved to a computer by using an external memory card.
In the aforementioned method, DRM content is reused in such as manner that an RO of DRM content is backed up and then restored in another terminal. With this method, the DRM content can be used only according to whether user authentication is successful. Therefore, when duration of use or the number of times of use the DRM content recorded in the RO are exhausted by the user, and thereafter if the backup file is restored and the user authentication process is performed, then the user authentication is successful and thus the DRM content can be reused. That is, when a conventional DRM backup and restoration technique is used, the user can use the DRM content without limitation, which results in a problem that right and interest of a DRM content provider cannot be protected.